As an adhesive, in-water adhesives are known which are useful for curing under wet conditions to bond materials to each other. As such an in-water adhesive, a fibrin glue which utilizes scleroprotein produced by reacting thrombin with fibrinogen, cyanoacrylate which cures through the reaction with water to adhere, a gelatin which cures upon the addition of glutaraldehyde, an epoxy resin and others are known, for example. In addition, a polymer having a catechol hydroxy group is also known (Patent Document 1).
Among these in-water adhesives, a fibrin glue, for example, cannot be mass-produced, and it may cause infections since it utilizes biological components. A cyanoacrylate is sometimes harmful to human bodies since a monomer before the curing has toxicity while cured product of cyanoacrylate is sufficiently safe. Glutaraldehyde also has toxicity, which induces curing by its addition to gelatin. An epoxy resin requires long curing time, and also requires heating for complete curing.
In contrast, in-water adhesives have been highly expected in various use applications such as a medical adhesive (an adhesive for implantation use) and surface adhesion of materials (concrete or metal) under wet or in water conditions. Therefore, further development of in-water adhesive is desired.